This is an outline for a DC electrical system designed for use on a small sailboat relying totally on battery power for weekend and holiday trips. It is a basic guideline that would be used to create more detailed specifications and was done free of charge (disclaimer) for its intended user.

AC system

• 30 amp shore power inlet (adapter to plug in extension cord)
• 30 amp shore power breaker
• Xantrex Freedom HF 1800 Watt inverter/40 amp 12 volt charger (modified sine wave output)
• Owner choice as far as numbers and locations of 115 volt convenience outlets or use outlets on inverter

DC system

• Four Trojan T-125 six volt wet cell lead acid golf cart batteries or equivalent (total 480 amp hours)
• Battery disconnect switch
• Separate disconnect/slash breaker for inverter DC power supply
• DC panel with appropriate number of breakers for intended loads

Notes

• System based on =240 amp hour consumption for three days and two nights aboard without recharging batteries
• Inverter/charger should allow recharging of batteries in approximately 120 to 240 minutes (depending on depth of discharge)
• Lighting is the largest amp hour consumer calculations assume LED type bulbs for all lights
• Inverter/charger is slightly more expensive than a comparable marine charger of the same output with the benefit of AC current when desired

References: ABYC E-11 (electrical standard) and Nigel Calders “Boat Owner’s Mechanical and Electrical Manual” Second Edition